I’ve been following this thread with interest. The line between Connellsville, PA and Cumberland, MD was B&O’s east-west Washington to Chicago mainline (now the CSX mainline). Your comments don’t say specifically what types of trains your grandfather operated, but in the days after Jan. 1, 1957, these numbers were all assigned to passenger diesels, as we have discussed. The 2409 was a B unit, and might have operated independently in the engine terminal, but it would have been a secondary booster on any mainline train, operating with at least one other unit with a standard cab.
If your grandfather operated pasenger trains on that line and ran GP7 3404 on a regular basis, it would be surprising because the standard road power for mainline passenger units on that line was the E unit. On the B&O, that meant E6A, E6B, E7A, E8A, E8AM, E8BM, or E9A’s in consists of two to four units.
1427 was an E7A built in 1945
1442 was an E8AM rebuilt from an EA in 1953
2409 was an E6B built in 1940
3404 was a passenger GP7 built in 1953
Passenger GP’s such as 3404 were not commonly used on B&O’s east-west mainline passenger trains, although they were sometimes pressed into service to substitute for a failed E unit. They were mostly used on commuter trains in the Washington-Baltimore pool, or on Pittsburgh commuter trains. I wonder whether your grandfather ever operated any of the Pittsburgh commuter trains. The Cincinnatian (Detroit-Cincinnati) was known to operate with them, and the Akron-Cleveland connection for numbers 17-18 used one for a while, but those operations were far from the Connellsville area. In the Connellsville area, the Washingtonian may have used them at some time. I wonder whether he ran the GP7 in freight service after train reductions had made it surplus for passenger service.
This is all interesting stuff. The more information you can provide, the more help we can provide. If you know specific date